Surgery in the abdomen is presently performed either through an incision that permits access to the operative site (laparotomy), or via rigid tubes inserted into small incisions in the abdominal wall through which the surgery is performed while being visualized by a camera (laparoscopy). There is no device or method for sewing or stapling through the flexible endoscope. Procedures performed through the flexible endoscope are primarily diagnostic in nature with the exception of biopsy and polypectomy.
There is a large segment of the population that suffers from morbid obesity, which has reached epidemic proportions in the USA. Obesity and its associated health problems have substantial economic consequences for the United States health care system; in 2003, the total costs attributable to obesity were estimated at $70 billion. For selected patients, surgical therapy, referred to as bariatric surgery, is the most effective treatment modality and has been recognized by the National Institutes of Health Consensus Panel as the only successful long-term treatment for morbid obesity. The Roux-en-Y gastric bypass, the procedure most commonly performed, combines a stomach restriction procedure and intestinal bypass, wherein part of the small intestine is stapled to the remaining stomach pouch.
The Roux-en-Y gastric bypass operation achieves successful outcomes in the majority of patients in terms of weight reduction and improvement of co morbid conditions, however it is a long and risky operation. When performed through a large abdominal incision, the procedure requires 2-5 hours of general anesthesia, many days in the hospital, significant use of medication for post operative pain and lengthy periods of convalescence.
Surgical procedures performed on the morbidly obese have a high incidence of complications because of the co morbid conditions that these patients suffer from. Oftentimes the surgeon has to dissect adhesions and free the bowel in order to get to the operative site. This procedure is quite difficult, and has to be performed before the actual bypass and gastric stapling operation has even begun.
When Roux-en-Y bypass surgery is performed laparoscopically, the incisions are smaller, but the abdomen is filled with a large amount of gas in order to distend it and enable the surgeon to perform the operation. The surgery is more difficult and typically takes 1-2 hours longer than the open operation. This requires longer anesthesia time increasing the danger to the patient. The distended abdomen impinges on the patient's lungs decreasing breathing capacity and adding morbidity. While this is a less invasive procedure than open surgery, it still entails significant complications and lengthy patient convalescence. Furthermore, because the surgery takes longer than open surgery, risk to the patient is increased from prolonged general anesthesia.
Providing a flexible suturing method and device to be used in conjunction with a flexible endoscope would significantly reduce the length and complexity of the surgery. Consequently, morbidity and mortality would be decreased, hospital stay shortened, and cost savings provided. Because flexible endoscopic procedures are typically performed under conscious sedation and are much less invasive, they are naturally less traumatic to the body. Convalescence is significantly shortened, postoperative pain is virtually eliminated and patients are ambulatory within hours after an endoscopic procedure.
Although there appear to be no commercial devices that enable suturing through the working channel of a flexible endoscope, U.S. Pat. No. 5,037,433 to Wilk et al. describes an endoscopic suturing device that comprises an endoscope and a needle having a mechanical spring bias construction tending to bend the needle into an arcuate configuration. The needle is disposed in a straightened configuration while inside the endoscope. The surgical instrument further comprises an ejector device in the form of an elongate flexible rod member slidably disposed inside the inner tubular member proximally of the needle for ejecting a needle, which mechanically assumes an arcuate configuration subsequent to its ejection.
Based on the disclosure and drawings of the '433 patent, the mechanical spring biased or elastic tendency of the needle tends to bend a needle in an arcuate configuration. As such, this pre-stressed plastic or metal needle may be deformed (i.e. straightened) by mechanical stresses on the needle being confined in a generally straight biopsy channel of an endoscope, deforming the needle to render it generally straight. The mechanical stresses are provided and maintained by the walls of the biopsy channel into which the needle is inserted. Once the needle is ejected out of the biopsy channel by a rod, the stresses are removed, and the free needle immediately assumes its pre-stressed arcuate configuration under the direction of its normal elastic properties.
The device described in the '433 patent presents various drawbacks and problems. First, the flexible endoscope is constructed in such a fashion as to allow only a 1 cm “stiff length” or less to pass through its biopsy or working channel. Any embodiment with a stiff length longer than 1 cm will not be capable of being passed through the working channel when the endoscope is bent, and will prevent the flexible endoscope from bending when housed inside its working channel. Consequently, only a device that is sufficiently malleable to bend relatively easily along with the endoscope may be passed through its working channel.
Suturing requires a rigid needle shaped in an arcuate form. When such a needle is plunged into the target tissue in one location, it will exit the tissue at a second location in a predictable manner because of the needle's arcuate configuration and stiff or rigid state. Accordingly, there are two important requirements that a suture needle must fulfill if it were to be used through the working channel of a flexible endoscope. On one hand, it must be malleable enough to be passed through the working channel of a flexible endoscope while an endoscope is bent to its maximum capacity, while on the other hand it must assume a rigid arcuate state in readiness for the suturing operation upon ejection. If the spring biased needle described in the '433 patent were to be sufficiently malleable to be passed through the working channel of an endoscope, it would surely be too malleable to enter and exit tissue in a reliable fashion. If a needle were to be formed from a material stiff enough to effectively and consistently enter and exit tissue, it would surely not be malleable enough pass through the working channel of a flexible endoscope.
A further problem that the device described in the '433 patent presents is its lack of anticipation of the difficulty presented in grasping the suture needle with the manipulation device. Just as in open and laparoscopic surgery, a suture needle must be grasped firmly so as not to rotate on its axis during the plunging of a needle into tissue. If the needle is permitted to rotate on its own axis it will only push against the tissue but will not enter it. Grasping a needle with jaw-closure-force being transmitted through a short rigid shaft, as is done during open or laparoscopic surgery is significantly different from grasping a needle with closure force being transmitted through a long flexible shaft. The latter forces required to close the jaws tightly are infinitely greater than in the former case. The '433 patent does not address such an issue. No special construction of the needle's shaft to enhance grasping is described, and the description of the grasping device does not anticipate any of the abovementioned difficulty.
Also, the '433 patent does not address the attachment of the suturing thread to the needle. Spring biased metals do not behave as stainless steel does. In the case of the stainless steel suture needle, the suture thread is inserted into a cavity at the proximal end of the needle and the metal is crimped over the thread. In the case of a needle made of a spring biased metal, the metal is too soft to retain the thread by mere crimping.
Lastly, when operating a needle through an endoscope, it is very difficult, if not impossible, to perform the rotating motion that is required to plunge the needle into the tissue, through the tissue, and out, as performed by the human hand. The simplest motion when working through an endoscope is the push-pull motion.